Abstract
The osmotic pressure generation was firstly presented as pressure-retarded osmosis (PRO) power generation by S. Loeb in 1976. The possibility and problems of the production of hydroelectric power by osmotic pressure generation have been discussed by S. Loeb, Takeo Honda, Fukuoka Water Service Consortium and SINTEF. They, however, have not been realized because of the problems in membranes though the power production cost is was low. In this paper those problems in the membrane are introduced and the way how to solve them is discussed.
